Electrode support arrangement



IN VEN TOR. 17/1 IVER h/ WAL AAC'E I I (III I l/l Y B m 55. d A 1 z I 1/ I F Nov. 1, 1960 ELECTRODE SUPPORT ARRANGEMENT United States Patent Cfice I 2,958,800 Patented Nov. 1, 1960 Milner W. Wallace, Westwood, NJ., assignor to Inter-- national Telephone and Telegraph Corporation, Nutley, NJ a corporation of Maryland Filed Mar. '5, 1959, Ser. No. 797,362

Claims. (Cl. 313-83) 2 This invention relates to electron discharge devices and more particularly to electron support arrangements therefor.

The wide utilization of electron discharge devices such as klystrons and traveling wave tubes in present day radar and communications systems has made it imperative that mass-production techniques be utilized in their manufacture in order to make such devices economically feasible and to insure a reasonable output of good quality devices in a highly competitive market.

Mass-production techniques can be most effectively applied in connection with assembly steps for properly aligning and supporting various electron discharge device electrodes. Formerly, the assembly of electrode support structure and their subsequent mounting and alignment required the employment of highly skilled workers. This technique is no longer feasible in that it is both expensive and time consuming and is productive of only a small number of devices. therefore, required which permits assembly of electron discharge devices by relatively unskilled labor and yet provides a tube which is rugged while possessing the accuracy and tolerances of more complicated prior art assembly techniques. Further, a technique is required which effectively minimizes the physical spacing of the elements of electrode support arrangements Without increasing the danger from breakdown between these elements.

It is, therefore, an object of this invention to provide an electrode support arrangement which is an improvement on prior art arrangements.

It is a further object to provide an electrode support arrangement which is amenable to mass-production techniques,

A feature of this invention is the utilization of a reference member having an opening disposed therein and an electrode support unit having a portion which registers with the opening and which extends therein. The electrode support unit portion has a retainer engaging means disposed thereon adjacent the reference member, and a retaining member which engages the retainer engaging means and the surface of the reference member at a predetermined location.

A further feature is the utilization of an electrode support unit which has a number of rods designed to register with openings in a reference member. The rods have protuberances or indentations on a portion of their surface adjacent the reference member wihch are so designed that in cooperation with a retaining member the rods can be rigidly and accurately arranged with respect to the reference member.

A still further feature is the utilization of an annular ring which engages notches in the rods of the electrode support unit; the annular ring having an inner diameter smaller than the diameter of a circle which could be circumscribed about the rods of the electrode support unit. The above mentioned and other objectors and features of this invention will become more apparent by reference A mass-production technique is,

to the following description of the embodiments thereof taken in conjunction with the accompanying drawings in which:

Fig. 1 is a longitudinal partial cross-sectional view of a traveling wave tube utilizing electrode support arrangements in accordance with the teachings of this invention.

Fig. 2 is a cross-sectional view taken along lines 22 of Fig. 1.

Fig. 3 is an enlarged cross-sectional cut-away view taken along lines 73-3 of Fig. 1.

Referring to Fig. 1, there is shown therein a traveling wave tube 1 having an input section 2, a radio frequency interaction portion 3 and an output section 4. Input section 2 includes a coaxial connector 5 which pierces vacuum envelope 6 and is utilized to couple an input signal from a point externally of traveling wave tube 1 to coaxial line transition 7. The input signal is then coupled to coaxial line portion 8 and from thence through two right angle bends to the helix 9 of radio frequency interaction portion 3. Radiofrequency interaction portion 3 and input section 2 are separated one from the other by a reference member 10 which is made of a magnetic material of high permeability such as Armco Iron and which functions as a gun barrier electrode to and in focusing an electron beam in its passage therethrough. The electron beam passes through reference member 10 by means of aperture 11 which is appropriately designed so that portions of a magnetic field supplied by a solenoid, not shown, emanate from portions of member 10 in a direction longitudinally of tube 1 in the direction in which an electron beam is projected. Reference member 10 includes an aperture disc 12 which is Welded'to reference member 10. An aperture 13 in disc 12 is disposed in overlying relationship with aperture 11 of reference member 10 and has aconical portion 14 which, in cooperation with other focusing elements, provides the proper electrostatic entrance conditions for an electron beam which is to be projected through apertures 11, 13. Reference member 10 need not be made of two portions as described hereinabove, but may be made of a single section of high permeability magnetic material. Member 10 has been designed to include disc 12 in the device of Fig. l solely for purposes of ease of fabrication.

Referring now to Figs. 1 and 2, it may be seen that aperture disc 12 contains three holes 15, spaced apart and spaced an equal radial distance from the center line of aperture disc 12. In Fig. 1, it may be seen that holes 15 in aperture disc 12 extend through aperture disc 12 and through reference member 10. Holes or openings 15 in their predetermined location, are adapted to receive an electrode support unit 16. Electrode support unit 16 includes a plurality of dielectric rods spaced 120 apart which can be utilized to support either the electrodes of an electron gun 17 or an electrode such as helix 9 of radio frequency interaction portion 3.

In connection with the mounting of an electrode support unit 16, such as an electron gun 17, it may be seen from a consideration of Fig. 1 that the various electrodes such as cathode 18, grid 19 and focus cylinder 20 are held in fixed spaced relationship by means of tabs 21 which are fixedly attached to dielectric rods 22. Dielectric rods 22, as can be seen in Fig. 2 are spaced 120 apart and their radial distance from a centerline is such that the rods 22 register with openings 15 and have portions 23 which extend into openings 15 and butt up against a portion of vacuum envelope 6. Alternatively, the openings 15 may be drilled to a given depth and need not extend all the way through reference member 10.

Dielectric rods 22 as shown in Figs. 1 and 2 have'a retainer engaging portion 24 disposed adjacent reference member 10 suchv that the retainer engaging means is raised slightly above the surface of aperture disc 12. Retainer engaging means 24 is shown in Figs. 1 and 2 as a notch cut in dielectric rods-:.22, but a raised portion or protuber nseqeuldibe utilized eqpally well in -accordance.

it is only necessary that a retainer engaging means. be. disposed on a portionofthe rod'which will-be engaged by a retainer member 25. Notches24. then, are designed to be engaged by a retaining member 25 which in Fig. 2 is shown-as; an annular-ring Retaining member 25 may be made of Monel, for instance, and should be sufiiciently,

flexible to permit-the portion-near the inner circumference thereof to engage the notches and yet permit retainer 2510, be adjusted such that the portion near the outer; circumference can; be held against the surface of aperture. disc 12, for fifictive welding thereto. In this manner, therefore, electron gun 17 is accurately positioned and radial motion is prevented by the registration of dielectric rods 2,2with holes 15 and the action of notches 24in cooperation with retaining member 25 prevents any motion of electrongun 17 in a longitudinal direction. Thus, all the elements involved in accurately positioning electron gun 17 may be preassembled and the only step required to provide an electron gun which is accurately aligned with a reference member is to insert the dielectric rods 22 of electrode support unit 16 into holes engage retaining member 25 in notches 24 and weld retaining member 25 to the surface of aperture disc 12.

In connection with retaining-member 25, it hasbeen noted that the annular. ring has an inner diameter less than the diameter of a circle which could be circumscribed about rods 22. Because of this, a cut out portion 26 has been'provided to permit retaining member 25 to be slipped over rods 22. When his desired to place retaining member 25in the notches, retaining member 25 is rotated such that portions of the inner circumference of retaining member 25 engage notches. 24. If, however, a raised portion instead of a notch isutilized to be engaged by retaining member 25, the inner diameter of retaining member 25 should be equal to the diameter of a circle which could be circumscribed about rods 22.

Referring to Figs. 1 and 3 there is shown therein another embodiment which is utilized in accordance with the teachings of this invention. In Fig. l, heiix 9 and its associated helix support rods 27-form an electrode support unit 16. The helix; support rods 27 are disposed 120 apart and are spaced an equal radial distance from a centerline and are adapted-to register with holes or openings 28 which have been drilled to a given depth adjacent aperturell and on surface 29 of reference member 14 opposite to that to which aperture disc 12 has been fixed. Helix support rods 27, like dielectric rods 22, contain notches adjacent surface 29 of reference member 10, the walls of, Which are designed to engage a retaining member similar to retaining member 25. In lieu of an annular ring type retaining member 25, tabs Seas shown in Fig. 3 may be utilized to engage the notches in the rods thereby effectively retaining the helix 9 and its associated support rods in fixed relationship with surface of reference member 10.

Thus, Fig. 1 clearly shows a reference member 19 having, electrode support units 16, disposed on opposite surfaces thereof and perpendicular to said reference member 10 to permit an electron beam to be projected therethrough without interference.

The helix 9 and its support rods 27 may be fixed to the referencemember 10 as described, hereinabove, however, the same technique may be utilized at output section 4 and electrode support unit 16 may be fixed to the collector element 31. Since it is not desirable to fix, a helix at both extremities, it should be affixed only at; Qnenend; and. if; afliztedeas described above... the, gun

4 barrier electrode is utilized as reference member 10 but if affixed at output section 4 a surface of the collector 31 may be used as a referencesurface.

It should be noted that the combination of the coacting notches 24 and retaining member 25 provides an arrangement which occupies a minimum amount of space, particularly in a direction lengthwise of electron discharge device 1. This factor is particularly important in view of the close proximity of retaining member 25 to elements of electron; gun 1-7- which may'have very high potentials applied thereto. Thus, by circumferentially engaging rods 22 with a reta-iner'25, as described hereinabove, electrode supportu-nit, 16 can be efiectively fixed and positioned and the danger from breakdown between tube elements is minimized,

While I have described above the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention as set forth in the objects thereof and in the accompanying claims.

I claim:

1. In an electron discharge device having an electron gun, adapted to project a beam of electrons along a given path and a gun barrier member having an aperture through which said beam is adaptedto pass; a combination therewith of a support structure for supporting said gun on said gun barrier member comprising a plurality of fixed dielectric rods, said gun barrier member having a. corresponding plurality of openings spaced apart in a circle about said aperture to receive the ends of said rods for retention, an annular member having an inner surface, and means associated with said inner surface of said annular member to eccentrically locate said annular member in surrounding relationship with said rods, and means cooperating with said inner surface of said annular member to concentrically locate said annular member in surroundingrelationship with said rods, said inner surface of said annular member cooperating with the surfaces of said rods to retain said rods in assembled relation with respect to said barrier member.

2. A structure according to claim 1 wherein said means to eccentrically locate said annular member includes a recess disposed on the inner surface of. said annular member.

3. A structure according to claim. 1 wherein said means to concentricallyv locate said annular member includes portions of reduced diameter in said rods adjacent the gun barrier element such that the annular member when shifted from its eccentric location to its concentric loca-v tion circumscribes a circle about the reduced portions of said rods.

4. In an electron discharge device having an electron gun adapted to project a beam of electrons along a given path and a gun barrier member having an aperture through which said beam is adapted to pass; the combination therewith of a support structure for supporting said gun on said gun barrier member comprising a plurality of fixed dielectric rods, said gun barrier member having a corresponding plurality of openings spaced apart in a circle about said aperture to receive the ends. of said rods for retention, said rods each having a portion of reduced diameter adjacent an end thereof, an annular element having an inner diameter less than thedistance betweenthe outer surfaces of said rods when assembled, said element having a recess on the inner edge thereof to receive one of said rods to allow sufficient spacing within said element to surround the assembled rods, means to.

mount said gun in assembled position on said rods to locate said gun in alignment with said aperture, and means securing said. element to said gun barrier member after said rods are located in said openings and said annular element has been shifted to disengage said recess frornsaid one rod and cause said element to engage each of the.,portians;,of...said rodsrofreduced diameter.

5. In an electron discharge device having an electron gun adapted to project a beam of electrons along a given path and a gun barrier member having an aperture through which said beam is adapted to pass; the combination therewith of a support structure for supporting said gun on said gun barrier member comprising a plurality of fixed dielectric rods, said gun barrier member having a corresponding plurality of openings spaced apart in a circle about said aperture to receive the ends of said rods for retention, said rods each having a notch in a 10 side surface thereof, an annular element having an inner diameter less than the distance between the outer surfaces of said rods when assembled, said element having a recess on the inner edge thereof to receive one of said rods :to allow sufiicient spacing Within said element to 15 surround the assembled rods, means to mount said gun in assembled position on said rods to locate said gun in alignment with said aperture, and means securing said element to said gun barrier member after said rods are located in said openings and said annular element has been shifted to disengage said recess from said one rod and cause said element to engage each of the notches of said rods.

References Cited in the file of this patent UNITED STATES PATENTS 2,150,323 Green Mar. 14, 1939 2,167,885 Glans Aug. 1, 1939 2,347,262 Herzog Apr. 25, 1944 2,708,727 Quate May 17, 1955 2,806,169 Robertson et al Sept. 10, 1957 

